10 July 2016

Commentary: 2016 U.S. Championship, Round 1 (Nakamura - Lenderman)

I'm back to analyzing a select series of commentary games from the April 2016 U.S. Championships. From major events I try to pull games of particular interest, either due to their openings or particular features that appear, for commentary work. I find that this complements analyzing your own games well, since it provides a much cleaner framework (typically GM-class games) for showing typical plans and how they can be executed.

Reviewing top-level games also reminds us how nobody is perfect and we can all get into problem situations, as GM Lenderman does in the below first-round game against GM Hikaru Nakamura, the eventual champion. I selected the game (highlighted in this ChessBase news article) because it shows a gambit and fianchetto approach against the Semi-Slav, which is my own preferred method of combating it. In terms of thematic material, the game very much highlights the classic ideas behind exploiting a lead in development, including grabbing space and opening lines for your pieces. Some key tactical themes also include the problem with hanging pieces, various pins, and defending pieces (in this case, a couple of key pawns for White) tactically while advancing your plan.

Nakamura, Hikaru (2787) - Lenderman, Alexsandr (2618)

Site: Saint Louis USA

Date: 2016.04.14

[...]1.d4d52.c4e63.¤f3¤f64.¤c3c6 the Semi-Slav 5.g3 here White goes with a kingside fianchetto approach, typical of a Catalan-style opening. I also prefer to play this way vs. a Semi-Slav style setup, although I'm not a 1. d4 player. This is also in effect a gambit approach, since Black can opt (as in the game) to take and try and hold the c-pawn. 5...dxc4

5...¤bd7 is most often played here and often signals a desire to keep the central structure and play for the e5-e4 break eventually.

6.¥g2b57.O-O¥b78.b3 this is the only game in the database with this move; Nakamura is often not afraid to be experimental in the opening. Most often played is Ne5, focused on targeting the c6 pawn, but White scores below par (45 percent).

Here's one game with a similar approach, although Nakamura accelerates the idea by a tempo. 8.¤e5£b69.b3cxb310.£xb3¥e711.¦d1O-O12.e4a513.¥e3a414.£c2£a515.a3¤a616.¤d3¦ac817.¦db1¥a818.¥d2£d819.e5¤d520.¤e4¤b621.¤dc5¤xc522.dxc5¤d723.¥f4g524.¥e3¤xe525.¦d1£c726.¤xg5¤g627.h4¦fd828.h5¤f829.£c3¦xd1+30.¦xd1¦d831.¦e1e532.f4¥f633.¤e4¥g734.f5£e735.h6¥h836.¥g5f637.¥e3£f738.¤d6£a739.£c2 1-0 (39) Hovhannisyan,M (2515)-Hautot,S (2360) Charleroi 2015

8...cxb3 here I wonder if this move wasn't in part driven by psychological factors, as a relatively safe-looking approach.

8...b4 looks the most testing, as Komodo assesses. 9.¤a4c310.a3a511.¤e5¤bd7 and Black looks fine, with the c6 pawn tactially protected, for example: 12.¤xc6?12...£c713.¤e5¥xg214.¢xg2¤xe515.dxe5£xe5µ

9.£xb3 now the game has transposed back to the database, with a very small but very favorable record for White (75 percent). 9...¥e710.¤e5a611.¦d1O-O12.¤e4 an effective move for the piece. The knight on c3 is not contributing materially to White's game, so Nakamura prepares to transfer it. Bg5 has been previously played here, with success, but Nakamura prefers to leave that square open for the Ne4 to move to. 12...£c7 (12...¤bd7!? would directly challenge the Ne5.) 13.¤g5 showing the value of targeting the traditionally weak f7 pawn, even when it is still protected by the Rf8, when the square e6 is also under attack. This is also a typical tactical theme in the Caro-Kann, where Black has to watch for sacrifices involving attacks on f7/e6. 13...a5 (13...h6?!14.¤gxf7¦xf715.£xe6 and Black has problems.) 14.¥h3 we are still far from the point where forced variations will get White anything. Nakamura bides his time and is content to engage in a maneuvering battle. Here e6 is targeted yet again, ignoring the (overprotected) c6 pawn. 14...a415.£c2 at this point the engine shows a slight plus for White. Black cannot have been too happy with the opening, as evident after the next move, which brings all the queenside pieces back to their original squares. 15...¥c8 a logical and correct move to protect e6, but it still must have been annoying to have to do. Black has little dynamic play available and his approach must be to hold onto the extra pawn and hope White's initiative proves fruitless. Normally Black would also try to look for a way to give back the material to fully equalize, for example in the move 17 variation below. 16.¥f4£d8 the queen has to move off the b8-h2 diagonal because of the threat of discovered attack. 17.¤g4 containing the obvious threat of exchanging the Nf6 and playing Qxh7 mate. 17...g6 this weakens the king position and helps make Black's edge more concrete.

17...¤bd7!?18.¥e5h619.¤xf6+¤xf620.¥xf6hxg521.¥xe7£xe722.£xc6¥d7 and the engine shows equality, but the position looks much easier for White to play.

18.¤xf6+¥xf619.¤e4¥g7

19...¥e7!? helping cover d6 may have been better, in light of White's 21st move, although it's understandable wanting to fill the kingside holes.

20.¥g2± the long diagonal becomes more important to occupy again, now that the sac threat against e6 is over. The engine's significant plus for White is easy to visualize here, given White's advantage in development (five pieces to one) and space. 20...£b621.¥d6 a good example of how to exploit better developed pieces and seize yet more space. 21...¦e822.¦ac1£d8 moving back to the original square. Black has to be frustrated by this point. 23.¥c5¥a624.¥b4£c7 playing defensively around the c6-pawn. But now Nakamura illustrates the principle of the benefits of opening the position when ahead in development, as well as highlighting the tactical danger of placing pieces (the Qc7) onto undefended squares. (24...¥b7) 25.d5!+⁠− this pawn lever effectively breaks open the position for White's pieces in the center. 25...exd526.¤d6 the point being a double attack (with the knight on the Re8 and the Bg2 on the d5 pawn; the c6 pawn is pinned against the Qc7 and no longer protects d5). 26...£d7 hoping that giving back material (i.e. the Re8) will exhaust White's initiative.

26...¦f827.¥xd5£e7 moving out of the pin still leaves White with a big advantage and Black with little he can do about it, for example 28.¥g2£e529.¦d2¥c830.¥c5¥d731.¤xb5¦c832.¤d6+⁠−

27.¤xe8£xe8 there is now less material on the board and the balance is roughly even, but White still has the far-better developed pieces, so continues to find success by opening lines in the center. 28.e4d429.e5 and the pawn is tactically protected, as either the bishop or queen taking on e5 would be followed up by Re1, losing Black material. 29...h5 this gives Black an escape square on h7, but there's little else he can do at this point. 30.f4 the pawn on d4 is now doomed and trying to keep the material balance doesn't help Black. 30...f631.¦xd4fxe532.fxe5¥c8

32...¥xe5? the pawn is still tactically protected 33.¦e4+⁠−

33.¦cd1 a simple yet powerful follow-up. 33...¥d7 Black blocks the penetration of a rook on d8, but now White has too many other threats, including on g6. 34.¦d6£xe535.£xg6£f536.¥c3 a beautiful move which puts maximum pressure on Black. Now the Bg7 is doomed.

36.¦f1 would be a less incisive but still practical way of winning. 36...£xg637.¦xg6+⁠−

36...£f737.¦f1£xg638.¦xg6 and after the bishop goes, White will have a mate in 5.